Felix Ehrat, the top lawyer at Swiss pharmaceutical company Novartis, has made a decision to step down from his role over the drugmaker's $1.2 million payment to President Donald Trump's personal lawyer Michael Cohen for healthcare policy lobbying services. "I take personal responsibility to bring the public debate on this matter to an end".

Ehrat will be replaced starting from June 1 by Shannon Thyme Klinger, who is now Novartis's ethics, risk and compliance officer. After the payments were exposed last week, Novartis has fought hard to distance Narasimhan from the scandal, insisting he was not involved in the contract.

But after Jimenez's people sat down with Cohen individually for the first time, "it was clear that he oversold his abilities", the former CEO said.

Novartis ended the $100,000-per-month contract, signed in early 2017 by Ehrat and former Novartis Chief Executive Joe Jimenez, this year.

Telecoms giant AT&T, which has acknowledged paying about $600,000 to Cohen and was also named by Daniels' lawyer, has also said it was a "big mistake" to hire Trump's lawyer, even as it maintained its actions were legal. Ehrat, has also apologised for co-signing a consulting contract with US President Trump'spersonal attorney in 2017. It said the payments continued because the contract could not have been terminated.

Jimenez spoke a day after his successor, Vas Narasimhan, conducted a conference call for 5,000 Novartis managers in which he said the company needs to rethink its approach to the use of consultants and lobbying firms, according to a person familiar with the situation. Novartis should have done more due diligence and "definitively parted ways" with Cohen as soon as it knew he wouldn't be able to help, the former CEO said.

The case is under examination by the Greek and US authorities. He maintained that Novartis never acted on any of Cohen's advice or tried to gain access to anyone in the administration. In an interview with Bloomberg, Jimenez said he hired Cohen thinking the lawyer had stopped working for Trump and turned to selling "his expertise in terms of knowing the personalities that were in the administration".